Capacitor having tantalum oxynitride film and method for making same

ABSTRACT

A capacitor has a tantalum oxynitride film. One method for making the film comprises forming a bottom plate electrode and then forming a tantalum oxide film on the bottom plate electrode. Nitrogen is introduced to form a tantalum oxynitride film. A top plate electrode is formed on the tantalum oxynitride film.

FIELD OF THE INVENTION

The present invention relates to semiconductor structures and methodsfor fabricating such structures in semiconductor integrated circuitsand, in particular, to forming capacitors for memory cells having highdielectric constant materials therein.

BACKGROUND OF THE INVENTION

Dynamic random access memories (DRAMs) are the most widely used form ofmemory integrated circuits to date. DRAMs are composed of memory cellarrays and peripheral circuitry required for cell access and externalinput and output. Each memory cell array is formed of a plurality ofmemory cells for storing bits of data. Typical memory cells are formedof a capacitor, for storing electric charges and a transistor, forcontrolling charge and discharge of the capacitor. Of primary concern ismaximizing the storage capacitance of each memory cell capacitor,particularly in light of the demand for 256 Mb DRAMs today and higherdensities in the future without increasing the chip space required toform the array. There is a need to decrease the chip space required toform each memory cell while maximizing the capacitance of the memorycells. The importance of high density DRAMs cannot be overstated intoday's competitive microelectronics market. Devices are becomingsmaller, but they are required to provide much more performance.

One way to achieve greater capacitance per unit area is to roughen thesurface of the capacitor plate, increasing the surface area. As can beseen from the following equation (I), the most important parametersinvolved in achieving maximum charge, Q, stored on the capacitor are thethickness of the capacitive dielectric film (t_(cdf)), the area of thecapacitor (A), and the dielectric constant (∈). The voltage appliedacross the capacitor plates is V.

Q=(∈·A·V)/t _(cdf)  (I)

Increasing the capacitor area (A) by forming the storage capacitor in atrench shape etched in the substrate is well known in the art, as wellas using a stacked capacitor structure. Stacked-type capacitors featurea major part of the capacitor extending over the gate electrode andfield isolating film of the underlying transistor. Such structures aregenerally composed of a lower plate electrode (consisting of a baseportion and a standing wall portion), a capacitive dielectric film, andan upper plate electrode. Other complex topographical lower plateelectrode configurations have also been used to maximize the capacitivearea (A) of a memory cell, such as fin-type, double-sided, and roughenedlower plate electrode structures produced using hemispherical grain(HSG) polysilicon.

In addition to increasing the capacitive surface area (A) of a memorycell, as can be seen from the above equation (I), the thickness of thecapacitive dielectric film (t_(cdf)) must be minimized to maintain themaximum charge stored on the capacitor. However, the capacitivedielectric film must also prevent direct electrical contact between thelower and upper electrodes to prevent the charge from decaying.

It is also desirable to utilize a capacitive dielectric film having ashigh of a dielectric constant (∈) as possible to further increase thecapacitance per unit area of a memory cell. One material that has a highdielectric constant is tantalum oxide, such as tantalum penta oxide(Ta₂O₅). Ta₂O₅ potentially has a dielectric constant (∈) of about 22,which is significantly greater than conventional silicon oxide, whichhas a dielectric constant (∈) of only about 3.9.

A capacitor of a memory cell formed with Ta₂O₅ insulator includes anelectrode. To attain adequate step coverage for the electrode on anintegrated circuit, the electrode may be initially formed with anorganometallic precursor that contains carbon.

After the capacitor is formed, the integrated circuit is subject to ahigh temperature processing step, such as borophosphosilicate glass(BPSG) reflow or polysilicon activation. During such heating, in thememory cell capacitor, carbon from the electrode diffuses into the Ta₂O₅insulator. The carbon in the Ta₂O₅ insulator forms a leakage mechanismthat renders the capacitor unusable. A relatively high leakage currentflows through the capacitor even when relatively small voltage isapplied across the capacitor. Therefore, there is a need for a capacitorthat has a relatively high capacitance per unit area, to ensure highdevice density, and a relatively low leakage current. There is also aneed for a dielectric material having a high dielectric constant that issubstantially unaffected by subsequent high temperature processingsteps.

SUMMARY OF THE INVENTION

A capacitor has a tantalum oxynitride film. One method for making thefilm comprises forming a bottom plate electrode and then forming atantalum oxide film on the bottom plate electrode. Nitrogen isintroduced to form a tantalum oxynitride film. A top plate electrode isformed on the tantalum oxynitride film. In another embodiment, ananti-fuse is formed in the same manner.

In one embodiment, the step of forming the tantalum oxide film comprisesthe steps of forming tantalum on the bottom electrode, and oxidizing thetantalum. In another embodiment, tantalum oxide film is formed bychemical vapor deposition with tantalum and oxygen sources. In yetanother embodiment, the tantalum oxide film is annealed to form atantalum oxynitride film Ta_(x)N_(y)O_(z), wherein (y+z)/x>2.5.

In another embodiment, the method of forming the capacitor includes thestep of forming a bottom plate electrode. A tantalum oxynitride film isformed on the bottom plate electrode. A top plate electrode is formed onthe tantalum oxynitride film. In one embodiment, the tantalum oxynitridefilm is formed by metal organo chemical vapor deposition with a nitrogensource that is hydrazene at a temperature between approximately 400 and600 degrees Celsius so as to form amorphous tantalum oxynitride.

In another embodiment, the invention is a capacitor that has a bottomplate electrode, a tantalum oxynitride film and a top plate electrode.In one embodiment, the tantalum oxynitride film is amorphous.

In one embodiment, the capacitor may be used in a memory array of amemory. The memory comprises the memory array, a control circuit,operatively coupled to the memory array, and address logic, operativelycoupled to the memory array and the control logic.

In yet another embodiment, the capacitor may be used in the memory arrayof a system. The system comprises a memory and a processor coupled tothe memory.

In yet a further embodiment, an antifuse is operated by applying avoltage across the electrodes of the capacitor having a tantalumoxynitride film. A hole is formed in the tantalum oxynitride film.

It is an advantage of the present invention that the capacitor has ahigh dielectric constant. It is also a benefit of the present inventionthat it is less affected by heat so as to have reduced leakage current.It is a further advantage of the invention that the capacitor hasenhanced reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional representation of a polysilicon electrodestacked, double-sided capacitor memory cell formed according to themethod of the invention, wherein the capacitor is stacked on asource/drain region of an underlying access transistor.

FIG. 1B is a cross-sectional representation of a trench-type capacitormemory cell formed according to the method of the invention.

FIG. 2 is a graphical representation of voltage versus capacitance forplanar tantalum penta oxide capacitive dielectric films formed accordingto the method of the invention compared to conventional silicon nitridecapacitive dielectric films.

FIG. 3A is an Auger plot of atomic concentrations in a memory cellhaving a tantalum oxide dielectric.

FIG. 3B is an Auger plot of atomic concentrations in a memory cellhaving a tantalum oxynitride dielectric

FIG. 4 is a block diagram of a memory having a capacitor in accordancewith the present invention.

FIG. 5 is a block diagram of the memory of FIG. 4 coupled to an externalsystem.

DESCRIPTION OF THE EMBODIMENTS

In the following detailed description of the invention, reference ismade to the accompanying drawings which form a part hereof, and in whichis shown, by way of illustration, specific embodiments in which theinvention may be practiced. In the drawings, like numerals describesubstantially similar components throughout the several views. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention. Other embodiments may be utilizedand structural, logical, and electrical changes may be made withoutdeparting from the scope of the present invention. The terms wafer andsubstrate used in the following description include any structure havingan exposed surface with which to form the integrated circuit (IC)structure of the invention. The term substrate is understood to includesemiconductor wafers. The term substrate is also used to refer tosemiconductor structures during processing, and may include other layersthat have been fabricated thereupon. Both wafer and substrate includedoped and undoped semiconductors, epitaxial semiconductor layerssupported by a base semiconductor or insulator, as well as othersemiconductor structures well known to one skilled in the art. The termconductor is understood to include semiconductors, and the terminsulator is defined to include any material that is less electricallyconductive than the materials referred to as conductors. The followingdetailed description is, therefore, not to be taken in a limiting sense.

FIGS 1A and 1B represent, generally, capacitors 100 of memory cellsformed in accordance with the method of the invention. The followingdescription details process steps utilized to form the capacitors 100.In particular, the process steps described are directed towards forminga tantalum oxynitride film 102 between bottom and top plate electrodes104, 106, respectively, of a capacitor 100.

FIG. 1A is a cross-sectional representation of a stacked, double-sidedcapacitor 100 formed according to the method of the invention, whereinthe capacitor 100 is stacked on a source/drain region 108 of anunderlying access transistor. The access transistor comprisessource/drain regions 108 on both sides of a gate structure, whichincludes a polysilicon gate 110 and gate oxide 112. The accesstransistor is fabricated in an active area of an underlying substrate101 that is defined by field oxide 114. Typically, the gate oxide 112and the field oxide 114 are formed using a conventional method, such asLOCal Oxidation of Silicon (LOCOS). The capacitor 100 is supported overthe source/drain region 108 by an insulating material 116, such asborophosphosilicate glass (BPSG), which reflows easily to producerounded comers over the gate 110, allowing better step coverage.

FIG. 1B is a cross-sectional representation of a trench-type capacitor100 formed according to the method of the invention, wherein the trenchshape is defined by sidewalls 118 and a bottom surface 120. FIGS. 1A and1B are meant to be illustrative, generally, of various capacitor 100shapes and electrode 104, 106 topographies that increase the surfacearea of the capacitor 100. The capacitor 100 shape and topography of theelectrodes 104 and 106 in a capacitor 100 are not critical to practicingthe invention. The capacitor 100 may also be formed as a fin-type,container-type, or crown-type capacitor. The scope of the invention isnot meant to be limited to those capacitors 100 illustrated.

In one embodiment, polysilicon, crystalline silicon, hemispherical grainpolysilicon, germanium, silicon-germanium, ruthenium, ruthenium oxide,iridium, iridium oxide, platinum, rhenium, and combinations thereof(deposited using chemical vapor deposition) is used as electrode 104,106 material in a capacitor 100. An increased surface area polysiliconbottom plate electrode 104 is formed over a supporting semiconductorstructure, as well known to one skilled in the art. The shape of thebottom plate electrode 104 may be stacked-type and trench-typestructures, as illustrated in FIGS. 1A and 1B, to provide an increasedcapacitive surface area for the capacitor 100. The topography of thebottom plate electrode 104 may include single-sided, double-sided, androughened lower plate electrode 104 topographies produced usinghemispherical grain (HSG) polysilicon. The lower plate 104 may beroughened on one side or both sides. The bottom plate electrode 104 canbe doped or undoped, and rough or smooth. Phosphorus is a common dopantfor a bottom plate electrode 104.

After cleaning the bottom plate electrode 104, such as with ahydrofluoric acid (HF) solution, the bottom plate electrode 104 issubjected to a surface treatment. The capacitor 100 is then annealed,such as by rapid thermal nitridation (RTN), rapid thermal oxidation(RTO), rapid thermal oxynitridation (RTN₂O), dry oxidation or highpressure oxidation.

A tantalum oxide film, such as tantalum penta oxide (Ta₂O₅), is thenformed on the bottom plate electrode. The tantalum oxide film ispreferably stoichiometric. Stoichiometric films have a lower defectdensity, resulting in a decreased leakage current. This is essential foroptimum electrical properties, particularly in capacitors 100.

Tantalum oxide film deposition is accomplished in a manner known tothose skilled in the art. In one embodiment, inorganic or organicprecursors, both liquids and/or solids, may be used for startingmaterials. Then, tantalum is deposited on the bottom electrode 104 ofthe capacitor 100. Then the tantalum is oxidized to form the tantalumoxide film. Alternatively, the tantalum oxide film can also be formed bychemical vapor deposition (CVD) with tantalum and oxide sources. In oneembodiment, using tantalum (V) ethoxide (Ta(OC₂H₅)₅) and oxygen (O₂)sources, a film of Ta₂O₅ can be deposited on the capacitor 100 with lowpressure CVD (LPCVD) at a temperature between approximately 400 and 500degrees Celsius.

The thickness of tantalum oxide film is approximately 30 to 200angstroms, and typically 90 angstroms. The formation of tantalum oxidefilms is further described in P. C. Fazan et al., “A High-C Capacitor(20.4 fF/μm²) with Ultrathin CVD—Ta₂O₅ Films Deposited on Rugged Poly-Sifor High Density DRAMs,” IEEE, pp. 263-266, 1992, and P. C. Fazan etal., “Ultrathin Ta₂O₅ Films on Rapid Thermal Nitrided Rugged Polysiliconfor High Density DRAMs,” International Conference on Solid State Devicesand Materials, pp. 697-698, 1992, both incorporated herein by reference.

After formation of the tantalum oxide film, the capacitor 100 isannealed in an environment containing oxygen. This anneal crystallizesand fills vacancies in the tantalum oxide film. This oxygen anneal maybe performed after the subsequently described introduction of nitrogen,such as by anneal, if the nitrogen introduction is performed at atemperature of greater than approximately 600 degrees Celsius. In oneembodiment, to form partially crystallized tantalum oxynitride, theoxygen anneal is performed after the nitrogen anneal, when the nitrogenintroduction is performed at a temperature between approximately 500 and750 degrees Celsius. In another embodiment, to form filly crystallizedtantalum oxynitride, the oxygen anneal is performed after the nitrogenanneal when the nitrogen introduction is performed at a temperaturebetween approximately 750 and 1050 degrees Celsius.

Subsequently, the tantalum oxide is transformed into tantalum oxynitride(Ta_(x)N_(y)O_(z)) film 102, where preferably (y+z)/x>2.5, byintroducing nitrogen into the tantalum oxide film. In one embodiment,the transformation is accomplished annealing the tantalum oxide, in afurnace or with rapid thermal processing (RTP), in a nitrogen atmosphereat a temperature ranging between approximately 25 and 1100 degreesCelsius. The nitrogen atmosphere may be nitrogen (N₂), ammonia (NH₃), orhydrazene (N₂H₄).

In one embodiment, the capacitor 100 is annealed in nitrogen atmosphereat a temperature range between approximately 200 and 825 degreesCelsius, and at a pressure range between approximately 1 and 50atmospheres. As a result, the tantalum oxynitride is formed to beamorphous. Amorphous tantalum oxynitride has a higher dielectricconstant than crystalline tantalum oxynitride, and therefore can formcapacitors having higher capacitance per area. Amorphous tantalumoxynitride can also be formed at temperatures between approximately 350and 575 degrees Celsius, and pressures between approximately 10milliTorr and 400 Torr. Preferably, the pressure is betweenapproximately 1 atmosphere and 30 atmospheres.

In another embodiment, the capacitor 100 is annealed in an ammoniaenvironment in a furnace at a temperature range between approximately500 and 1050 degrees Celsius and at a pressure less than 5 torr forapproximately 5 minutes. Alternatively, the capacitor 100 can be furnaceannealed between approximately 1 and 60 minutes at a pressure betweenapproximately 10 milliTorr and 1 atmosphere. In another embodiment, thecapacitor 100 is annealed in a nitrogen environment, such as ammonia,with RTP between approximately 700 and 1050 degrees Celsius for a timebetween approximately 10 and 120 seconds. As a result of annealing, thetantalum oxide film is converted to a tantalum oxynitride film 102.

In yet a further embodiment, the capacitor 100 is annealed in a nitrogenatmosphere in the presence of a plasma. The plasma may be a plasma forenhanced deposition, such as high density plasma (HDP), a radiofrequency (RF) plasma, or an electron cyclotron resonance (ECR) plasma,or a remote plasma. The nitrogen atmosphere may include the previouslydescribed nitrogen sources, N₂O, NO, O₃, O₂ or a combination thereof.

In yet another embodiment, the tantalum oxide film can be transformedinto tantalum oxynitride film 102 by implanting nitrogen ions into thetantalum oxide. Ion implantation of nitrogen is known to persons skilledin the art.

In an alternative embodiment, the tantalum oxynitride film 102 can bedirectly formed by CVD, such as metal organo CVD (MOCVD), with tantalumand nitrogen sources, in a manner known to those skilled in the art. Thetantalum source may be tantalum (V) ethoxide (Ta(OC₂H₅)). The nitrogensource may be N₂, NH₃, N₂O, N₂H₄, monomethyl hydrazene (MMH), or othernitrogen sources. The nitrogen source may be introduced to the capacitor100 in the presence of one of the plasmas described above. Typically,the tantalum oxynitride film 102 formed by the methods described abovehas a crystalline structure.

However, it may be desirable to create tantalum oxynitride film 102 thatis amorphous. To form an amorphous tantalum oxynitride film 102, avolatile nitrogen source such as hydrazene, or hydrazene derivativessuch as monomethyl hydrazene (MMH), is used. As a result, the MOCVDprocess can be performed at relatively lower temperatures of betweenapproximately 300 and 600 degrees Celsius to form the amorphous tantalumoxynitride film 102. Preferably, the temperature ranges between 400 and550 degrees Celsius.

In another embodiment, to diminish the amount of carbon thatsubsequently enters the tantalum oxynitride film 102 to form a leakagemechanism, silicon is preferably formed on the tantalum oxynitride film102. Thus, in one embodiment, a silicon nitridation process is used. Thememory cell 100 is exposed to a combination of silicon and nitrogensources. The silicon sources include silane, disilane anddichlorosilane. The nitrogen sources include N₂, NH₃, N₂H₄, N₂O, andMMH. In one embodiment, the silane and nitrogen are respectivelydisilane and ammonia combined in a one to five ratio. In anotherembodiment, this process is conducted for a sufficiently small period oftime, such as less than the incubation time, so that no, or aninsubstantial amount of, silicon nitride is actually formed on thecapacitor 100.

After tantalum oxynitridation film 102 formation, the top electrode 106is formed. In one embodiment, the top electrode 106 is formed fromtitanium nitride (TiN) either formed by CVD with an organic precursorsuch as tetradimethyl amino titanium (TDMAT), or by a high-temperatureCVD process with inorganic precursors such as TiCl₄ and NH₃.Alternatively, the top electrode 106 may be initially formed withtungsten nitride. Subsequent processing of the capacitor 100 iscompleted in a manner known to those skilled in the art. For example,the capacitor 100 is later subjected to high temperature processingsteps, such as BPSG reflow or polysilicon activation.

The resulting capacitor 100 has reduced leakage current when adielectric that is tantalum oxynitride film 102 is used rather thantantalum oxide film. This beneficial property is illustrated in FIG. 2which shows the voltage required to induce a leakage current density of3×10⁻⁷ A/cm² in a capacitor 100. FIG. 2 illustrates that such currentdensity occurs in a capacitor 100 having a tantalum oxide filmdielectric with the application of zero volts (201). However, at least0.8 volts must be applied across a memory cell 100 with a tantalumoxynitride film 102 dielectric to induce the same current density (202).Thus, the tantalum oxynitride film 102 in a capacitor 100 reduces theleakage current density.

These benefits arise because the formation of the tantalum oxynitridefilm 102 and introduction of silicon, described above, diminish theamount of carbon that enters the tantalum oxynitride film 102 during thehigh temperature processing steps. FIGS. 3A and 3B are Auger plots ofthe relative concentrations of atomic concentrations of a capacitor 100having dielectrics that are respectively tantalum oxide and tantalumoxynitride. FIG. 3A and 3B show that the concentration of carbon carbidein the capacitor 100 having a tantalum oxynitride film 102 (304) issubstantially less then for a capacitor 100 having a tantalum oxide film(302).

Additionally, the capacitors 100 made with the aforementioned processhave significantly enhanced reliability resulting from the use of thetantalum oxynitride film 102. Specifically, the capacitor 100 hasenhanced time-dependent dielectric breakdown and rupture voltage.

FIGS. 2 and 3 are illustrative of the present invention. However,different results may occur if process parameters, such as the lengthand temperature of the high temperature processing steps, vary.

The present invention can be performed in a single tool without exposingthe capacitor 100 to the atmosphere. For example the nitridization ofthe bottom electrode 104, oxidation of the tantalum, and thenitridization of the tantalum oxide can be accomplished in a singletool. As a result, undesired effects, such as oxidation of the bottomelectrode, can be diminished. Also, the stoichiometry of the tantalumoxynitride film 102 can be more tightly controlled.

The aforementioned processes may be used to form capacitors 100 in amemory array 402 of a memory 400, such as a dynamic random accessmemory, as illustrated in FIG. 4. The memory 400 may include a memoryarray 402, control logic 404, and address logic 406 coupled in a mannerknown to one skilled in the art and exemplified in FIG. 4. The memory400 may be coupled to an external system 524, such as a processor, asillustrated in FIG. 5.

The capacitor 100 made according to the present invention may also beused as an antifuse, for example, for programming redundant elements ina memory 400. The antifuse is activated in the following manner. A largevoltage is applied across the electrodes 104, 106 of the capacitor 100.A hole is formed in the tantalum oxynitride film 102. As a result, thecapacitor 100 becomes a resistor having a resistance betweenapproximately 1000 and 6000 ohms, typically about 3000 ohms. Theresistance may also range between approximately 500 and 7000 ohms. Theantifuse is superior to other antifuse structures because it has arelatively lower resistance.

Conclusion

It is an advantage of the present invention that it forms a capacitorhaving relatively high capacitance to area ratio. It is also a benefitof the present invention that it is less affected by heat so as to havea diminished leakage current. It is also an advantage of the inventionthat the capacitor has enhanced reliability. It is a further benefit ofthe present invention that it can be performed in a single tool withoutexposing the memory cell 100 to the atmosphere. It is to be understoodthat the above description is intended to be illustrative, and notrestrictive. Many other embodiments will be apparent to those of skillin the art upon reviewing the above description. The scope of theinvention should, therefore, be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled.

What is claimed is:
 1. A method for fabricating a capacitor on anintegrated circuit, comprising: forming a bottom plate electrode;forming a tantalum oxide film on the bottom plate electrode; introducingnitrogen into the tantalum oxide film to form a tantalum oxynitridefilm, wherein the nitrogen is introduced at temperatures greater than800 degrees Celsius; annealing the tantalum oxynitride film in aenvironment containing oxygen, wherein annealing is performed afterintroducing nitrogen; and forming a top plate electrode on the tantalumoxynitride film.
 2. The method of claim 1, forming the tantalum oxidefilm comprises: forming tantalum on the bottom electrode; and oxidizingthe tantalum.
 3. The method of claim 1, wherein forming the tantalumoxide film comprises forming a tantalum oxide film by low pressurechemical vapor deposition with tantalum and oxygen sources at atemperature between approximately 400 and 500 degrees Celsius.
 4. Themethod of claim 3, wherein forming the tantalum oxide film includesforming the film to a thickness of about 90 Angstroms.
 5. The method ofclaim 1, whereinintroducing nitrogen compromises implanting nitrogenions into the tantalum oxide film to form the tantalum oxynitride film.6. The method of claim 1, wherein introducing nitrogen compromisesannealing the tantalum oxide film in a nitrogen atmosphere in thepresence of a plasma.
 7. The method of claim 1, wherein the methodfurther includes forming a silicon nitride film on the tantalumoxynitride film using a process of silicon nitridation.
 8. The method ofclaim 7, wherein silicon nitridation comprises exposing the capacitor toa combination of silicon and nitrogen sources.
 9. The method of claim 8,wherein using a process of silicon nitridation comprises exposing thecapacitor to disilane and ammonia combined respectively in a one to fiveratio.
 10. The method of claim 8, wherein the silicon source for siliconnitridation is selected from a group consisting of silane, disilane anddichlorosilane.
 11. The method of claim 8, wherein the nitrogen sourcefor silicon nitridation is selected from a group consisting of N₂, NH₃,N₂H₄, N₂O, and monomethyl hydrazene (MMH).
 12. The method of claim 8which includes conducting the silicon nitridation such that a minimalamount or no silicon nitride is formed on the capacitor.
 13. A methodfor fabricating a capacitor in an integrated circuit, comprising:forming a bottom plate electrode; forming a tantalum oxide film on thebottom plate electrode; introducing nitrogen into the tantalum oxidefilm to form a tantalum oxynitride film, wherein introducing nitrogencomprises annealing the tantalum oxide film in a nitrogen atmosphere ata temperature range between approximately 800 and 1100 degrees Celsius;annealing the tantalum oxynitride film in an environment containingoxygen, wherein annealing is performed after introducing nitrogen; andforming a top plate electrode on the tantalum oxynitride film.
 14. Themethod of claim 13, wherein annealing comprises annealing the tantalumoxide film in a nitrogen atmosphere, wherein the nitrogen atmosphere isone of a group consisting of: N₂, NH₃, and N₂H₄.
 15. The method of claim13, wherein annealing comprises annealing the tantalum oxide film in anitrogen atmosphere at a temperature of approximately 825 degreesCelsius at a pressure range between approximately 1 and 50 atmospheres.16. A method for fabricating a capacitor in an integrated circuit,comprising: forming a bottom plate electrode; forming a tantalum oxidefilm on the bottom plate electrode; introducing nitrogen into thetantalum oxide film to form a tantalum oxynitride film, whereinintroducing nitrogen comprises annealing in a furnace having an ammoniaatmosphere at a temperature range between approximately 800 and 1050degrees Celsius, and at a pressure less than 5 torr, for approximatelyfive minutes; annealing the tantalum oxynitride film in an environmentcontaining oxygen, wherein annealing is performed after introducingnitrogen; and forming a top plate electrode on the tantalum oxynitridefilm.
 17. A method for fabricating a capacitor in an integrated circuit,comprising: forming a bottom plate electrode; forming a tantalum oxidefilm on the bottom plate electrode; introducing nitrogen into thetantalum oxide film to form a tantalum oxynitride film, whereinintroducing nitrogen comprises rapid thermal processing in a nitrogenatmosphere at a temperature between approximately 800 and 1050 degreesCelsius for a time between approximately 10 and 120 seconds; annealingthe tantalum oxynitride film in an environment containing oxygen,wherein annealing is performed after introducing nitrogen; and forming atop plate electrode on the tantalum oxynitride film.
 18. The method ofclaim 18, wherein the nitrogen source is introduced to the capacitor inthe presence of a remote plasma.
 19. A method for fabricating acapacitor, comprising: forming a bottom plate electrode; forming atantalum oxynitride film Ta_(x)N_(y)O₂, on the bottom plate electrode;forming a top plate electrode on the tantalum oxynitride film; whereinforming the tantalum oxynitride film comprises forming tantalumoxynitride film by metal organo chemical vapor deposition with tantalumand nitrogen sources; and wherein nitrogen is introduced at atemperature above 600 degrees Celsius before annealing the tantalumoxynitride film in an environment containing oxygen.
 20. The method ofclaim 18, wherein the nitrogen source is introduced to the capacitor inthe presence of a plasma for enhanced deposition.
 21. The method ofclaim 18, wherein the nitrogen source is one of a group consisting ofhydrazene and hydrazene derivatives.
 22. A method of fabricating acapacitor in an integrated circuit, comprising: forming a bottom plateelectrode; forming a tantalum oxide film on the bottom plate electrode;introducing nitrogen into the tantalum oxide film to form a tantalumoxynitride film, wherein nitrogen is introduced as one of a groupconsisting of N₂O, NO, and N₂H₄ and wherein nitrogen is introduced at apressure higher than atmospheric pressure and at temperatures greaterthan 800 degrees Celsius; annealing the tantalum oxynitride film in anenvironment containing oxygen, wherein annealing is performed afterintroducing nitrogen; forming a top plate electrode on the tantalumoxynitride film.
 23. A method for fabricating a capacitor on anintegrated circuit, comprising: forming a bottom plate electrode;forming a tantalum oxide film on the bottom plate electrode; introducingnitrogen into the tantalum oxide film to form a tantalum oxynitridefilm, wherein nitrogen is introduced at temperatures greater thanapproximately 600 degrees Celsius; annealing the tantalum oxynitridefilm in an environment containing oxygen; forming a silicon film on thetantalum oxynitride film using a process of silicon nitridation, whereinsilicon nitridation comprises exposing the capacitor to a combination ofsilicon and nitrogen sources, and wherein using a process of siliconnitridation comprises exposing the capacitor to disilane and ammoniacombined respectively in a one to five ratio; and forming a top plateelectrode on the silicon film.